DominicCobb said:

Whatever it is, it looks good. My guess is it was supposed to be for 3D usage.

But wait, didn't TPM 3D just use the 2011 version?

Maybe this was a 4K restoration that was scaled down for the Blu-ray release (and then shat on a bit).

If you're referring to the existing blu-ray, no, that wouldn't be the situation here. That release used the 2004 Lowry masters, with a few additional tweaks.

TPM, meanwhile, was two birds with one stone. They went back to ILM's film-out tapes, which were still readable after more than a decade, and reconstructed the movie digitally. This gave them not only a digital master that was even closer to the true original negatives (and ideal for the blu-ray transfer), but also an excellent starting point for the 3D conversion.